Search NASA⌕ Search

DOE OSTI · 1202843

Materials Data on Na4Cu2S3 by Materials Project

Abstract

Na4Cu2S3 crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. there are seven inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to four equivalent S2- atoms to form a mixture of corner and edge-sharing NaS4 tetrahedra. All Na–S bond lengths are 2.74 Å. In the second Na1+ site, Na1+ is bonded to four equivalent S2- atoms to form a mixture of corner and edge-sharing NaS4 tetrahedra. All Na–S bond lengths are 2.88 Å. In the third Na1+ site, Na1+ is bonded to four S2- atoms to form a mixture of distorted corner and edge-sharing NaS4 tetrahedra. There are two shorter (2.87 Å) and two longer (2.89 Å) Na–S bond lengths. In the fourth Na1+ site, Na1+ is bonded to four S2- atoms to form a mixture of corner and edge-sharing NaS4 tetrahedra. There are two shorter (2.81 Å) and two longer (2.85 Å) Na–S bond lengths. In the fifth Na1+ site, Na1+ is bonded to four S2- atoms to form a mixture of corner and edge-sharing NaS4 tetrahedra. There are two shorter (2.85 Å) and two longer (2.87 Å) Na–S bond lengths. In the sixth Na1+ site, Na1+ is bonded to four S2- atoms to form a mixture of corner and edge-sharing NaS4 tetrahedra. There are a spread of Na–S bond distances ranging from 2.76–2.84 Å. In the seventh Na1+ site, Na1+ is bonded to four S2- atoms to form a mixture of corner and edge-sharing NaS4 tetrahedra. There are a spread of Na–S bond distances ranging from 2.79–2.84 Å. There are two inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded in a linear geometry to two S2- atoms. There are one shorter (2.16 Å) and one longer (2.17 Å) Cu–S bond lengths. In the second Cu1+ site, Cu1+ is bonded in a linear geometry to two S2- atoms. There are one shorter (2.15 Å) and one longer (2.16 Å) Cu–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded to four Na1+ and two Cu1+ atoms to form SNa4Cu2 octahedra that share corners with four equivalent SNa4Cu2 octahedra, corners with three equivalent SNa6Cu pentagonal bipyramids, and an edgeedge with one SNa6Cu pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 59–68°. In the second S2- site, S2- is bonded in a 7-coordinate geometry to six Na1+ and one Cu1+ atom. In the third S2- site, S2- is bonded to six Na1+ and one Cu1+ atom to form distorted SNa6Cu pentagonal bipyramids that share corners with three equivalent SNa4Cu2 octahedra, a cornercorner with one SNa6Cu pentagonal bipyramid, an edgeedge with one SNa4Cu2 octahedra, and edges with three equivalent SNa6Cu pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 5–64°.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

2020-04-29. Materials Data on Na4Cu2S3 by Materials Project. https://doi.org/10.17188/1202843

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

Cyclic moisture reactivation of calcium sorbents for long duration thermochemical energy storage

The transition to a flexible and reliable energy infrastructure, using electro-thermal energy generation technologies such as geothermal, concentrated solar power, and nuclear, usually demands simultaneous advancement of thermal energy storage (TES) to support on-demand electricity generation and industrial applications while mitigating the inherent intermittency of renewable energy sources and power outages from direct energy generation. Among TES technologies, thermochemical energy storage (TCES) based on calcium looping emerges as a compelling high-power energy storage candidate due to its high reaction enthalpy, compatibility with elevated operating temperatures, and abundance of low-cost materials. However, the long-term durability of calcium-based sorbents for TCES is hindered by surface sintering and particle aggregation, leading to performance degradation over repeated thermal cycles. This study explores a moisture hydration-based strategy to regenerate a degraded calcium sorbent and mitigate performance degradation for long duration TCES. The addition of moisture transforms calcium oxide into calcium hydroxide and produces intercalation water layers, associated with a regenerated surface area and reduced calcium oxide crystallite size. Both these effects are beneficial in restoring the sorbents' reactivity for carbonization. Additionally, an optimized hydration-assisted reactivation protocol balances the recovered energy storage capacity with heating penalty required for moisture removal from hydrated samples, resulting in an enhanced energy storage capacity up to 176% compared to benchmark sorbents that undergo cycling without reactivation after 60 cycles. In conclusion, these results highlight the potential of hydration-assisted reactivation to enhance the long-term performance of TCES, providing an effective pathway to advancing electro-thermal storage technologies.

36 MATERIALS SCIENCE↗